And so another banking empire unravels. As Barclays begins to pare back the investment bank built up under its former boss Bob Diamond, here comes Royal Bank of Scotland spinning off the US fiefdom created by Fred Goodwin.

Except, of course, that floating the Citizens business in the US - which has a 1,370 strong-branch network across 12 states - will release value for bailed-out RBS.

The bank is appeasing regulators, who want to see it bolstered by freed up capital, and to placate politicians who are unconvinced that a bank 81%-owned by UK taxpayers needs a US presence. In filing documents with the US regulator, RBS boss, Ross McEwan, has shown he is ready to fire the starting gun on the sell off.

The filing also provides insights into pay deals that might not otherwise have been disclosed. Ellen Alemany, who ran the US arm for five years until last autumn, was handed $7.5m (£4.45m) last year including a $500,000 consultancy fee to help her ease her replacement – Bruce van Saun – into her seat.

Van Saun was paid $5.6m and could be handed more than $12m if a rival bank buys Citizens and ousts him from his position.

The filing also mentions the impact of the EU bonus cap, which limits bonuses to one times salary – or twice if shareholders approve – and applies to the US operation as long it retains ties to RBS, which are likely to remain for a few years yet via a rump shareholding.

The UK government has already blocked an attempt by RBS to pay bonuses of twice times salary. Given only two of its employees (excluding the departed Alemany) in the US fall under the scope of the cap, it begs the question what all the fuss is about.

Another cautionary tale for any European bank targeting growth across the Atlantic.